Circuit arrangement for electronic amplifiers



Jan. 1, 1935. H. GUTMANN 1,985,923'

CIRCUIT ARRANGEMENT FOR ELECTRONIC AMPLIFIERS Filed March 6, 1951 maxim,

lawman INVEN TOR HERBERT GUTMA BY j ATTORNEY I ,1 p enmmrdn Et -(mm .f

n pumibn mmn s,1931, Ser'al No. 520,541

:HerbertGutmann; Berlin, Germany,-assignor'-"toTelefunkengfiesellschaft,fiir Drahtlose Teleg c .1!!! 1 H: Ber .Gcrmara'corpora n oelny Aprili23, r939 ferent types.

amplifier"arrangement};particularly for audio free quency and radio freuenc "amplificationwork which comprises twoseries-connected tubes of Ythe same type. Ifboth" tubes are simultaneously supplied with gridpotential of like value, such an arrangement results in the same slopeand only half the plate reaction of a single tube. Hence, this circuitscheme results in the inverse condition obtained with the usual parallelconnection in which, for two similar tubes, the slope is doubled whilethe plate reaction re mains unchanged.

Series connection, of course, is useful also for more than two tubes aswell as for tubes of dif- It could-also be combined with parallelconnection so that any desired plate re,- action and any desired slopeinside certain limits are obtainable. r

Circuit schemes according to this invention may be used to advantage incases where an existent grid alternating current potential is to beamplified a certain amount, and where a tube which possesses the platereaction required therefor,

dueto its limited permissible plate direct current has such a narrowgrid width that the available alternating current potential can not beaccommodated under conditions free from distortion. In thiscase,according to this invention, two tubes with double plate reaction (thatis to say, double grid width for the sameplatepoties and harmful efiectssince it is distributed over the two tubes.

The circuit scheme here disclosed may be used to advantage for receptionwhere it is desired to tune two circuits independently of each other todifferent band widths and where the incoming energy is to be combinedagain. g

A third application of the circuit scheme here disclosed is forfrequency doubling or frequency multiplication.

tential supply V. has its positive pole connected by way of the consumeror load (transformencoil or resistance) with the plate of tube 1-, whilethe negative pole is united with the filamentpf tube I II. In parallelrelation to each tube iis suitably 3a. shows in what way such frequencydoubling tiple of'the input frequency. The invention is shown in sixillustrations.

provided a, high. impedance or theseries combinaw tion comprising {aresistance] R-and capacity C (though, 1in eertam cimmnst nce; R Inlay.be: re: placed by an inductance coil).'.By ondensers Gland C2 eachtube'receive'st e filament 5 potential required for the. startingofia'plate our rent. Resistances R1 and R2 serve the purpose to make thetime-constant of R and C so high that the audiofrequency variations ofthe lowest'ocg curing frequency will not yet occasion any apprel0 ciabledischarges of the condensers. Furthermore, R1 and R2 must be so chosenthat they will not impair the amplification of the tube. Hence, R1 andR2 mustbe high compared with the internal resistance of the tube andalso great compared with for direct current and alternatin'gcurrentheat- 25 lead (see Figs. la and 'lb).

What is concernedin the case of Fig. 2 is a radio frequency amplifier inwhich the input circuits of the two series-connected electron tubes aretuned 0 to different band widths. 1 V i Figs. 3a. and 3b illustratearrangements for frequency multiplication. The two tubes-are connectedaudion-fashion in this illustration. The

ing also from a resistance Wl', W2 in the plate ends of the grid windingof one tube are transposed with those of the other tube, with the re-'sult that one half-cycle is amplified by one tube, v and the other bythe respective other tube. Fig.

may be continuedin additional stages. In Fig. 3b frequencymultiplication is effected in a single such stage by that the plate coilis caused to react inductively upon the grid coils, and by that theplate circuit 'is'ituned to the desired 2 mul- 45 I claim:

1. In combination with a source of oscillations,

a pair of space discharge devices having separate input circuits and acommon'output circuit, a

source of space current for said devices, the space 0 V paths, of saiddevices acting as potential dividers in connection with said source andmeans for coupling the input circuit of each of said devicesindependently/to said source of oscillations, a load circuit, means forcoupling the common output devices forming a series circuit with boththe space paths of said devices, meansior coupling the input circuit ofeach of said devices-independently to said first named source, a commonutilizing circuit, means for transferring energy from the common outputcircuit of said devices to aload circuit, said last named meansbeingalso in series with the spaced paths of said devices and the source ofspace current. a r

3. In combination with a source of a pair of space discharge deviceshaving input and output circuits, a source of space current for saiddevices, the space paths ofsaid devices and said source of currentforming a series circuit, means for coupling the input circuit of eachof said devices independently to said source ofooscillations, said inputcircuits being tuned .to' different frequencies.

4. A circuit as described in the next preceding claim wherein one of theinput circuits is tuned slightly above the frequency of the oscillationsfrom the source whereas the other input circuit is tuned slightly belowthe frequency of said oscillations; '1 f r 5. An amplifier foramplifying .a band of frequencies comprising at least two spacedischarge devices having separate and distinct input circuits andacommon output circuit, a source of space current for's aid devices,said common output" circuits including the spaced paths of said devices,andthe source ofispace current all in series and a shunt-[circuitconnected across the space path of each of said devices comprising acon-' denser in series with an impedance device the shunt circuits andsaid source of space current forming a series circuit, the impedance ofeach of the impedance devices being higher than the in- 'ternalresistance of the related space discharge device and considerablygreater than the reactance of its associatedicondenser. at the lowestfre quency of said bandflof freq'u'eriCies'Lj i HERBE T GUTIMANN.

